The characterisation of materials with a view to improving or optimising formulations or to identifying new and useful compositions usually requires the performance and recordal of large numbers of experiments. The preparation of samples for such experiments is time consuming and prone through poor human performance (owing to fatigue, boredom etc in performing repetitive operations) to error in measurement of quantities of ingredients and/or recordal of volumes, weights and other details relating thereto. The nature of the ingredients themselves, for example low viscosity liquids, medium and high viscosity liquids, thixotropic liquids, powders etc, owing to the difficulty in accurately dispensing them, may compound such human-generated errors or give rise to other potential errors during the dispensation of such ingredients.
Powders, in particular, are frequently difficult to dispense accurately and repeatedly, especially when dispensed in small amounts and in parallel. Some of the difficulties that may be experienced are initiating flow of powder from a sample holder, minimising powder retention in the sample holder and, when dispensing multiple samples, initiating dispensation of the samples at the same time. The simultaneous dispensation of a number of powders into fluids may be particularly important to ensure the sample histories are as identical as it is practical to achieve. Additionally, the dispensation of powders into fluids, especially liquids, has to ensure the powders are in intimate contact with the fluid medium. With many powders, for example starches and hydrocolloids, bulk contact with liquid tends to result in the powders agglomerating in clumps with the majority of the material not being wetted out by the liquid. Consequently, it is frequently necessary to add powders to fluids incrementally.
It is an object of the present invention to provide novel methods of and apparatus for dispensing powder samples. In particular, it is a further object of the present invention to provide novel methods of and apparatus for dispensing powder samples in parallel in which one or more of the aforementioned disadvantages is/are reduced or eliminated.